Prior art apparatus for winding a weft thread onto spools of carriers are disposed within an arcuate portion of a closed trajectory of movement of the carriers and include a disk rotatable in a horizontal plane, a stationary toothed sector installed coaxially with the disk, and winding members driven into rotation by satellite gears periodically engaging the stationary toothed sector.
The winding members of a great variety of designs are constantly meshed with the satellite gears and, like the latter, are mounted on the rotatable disk. The surface of the toothed sector, along which the satellite gears run, determines the extent of a winding zone, i.e., determines the portion of the closed trajectory within which the weft thread is wound onto the spools of the moving carriers. In this case, irrespective of the design of the winding members, the methods whereby the end of the weft thread is wounded and gripped during winding and design of the devices used to propel the carriers, the winding process begins immediately upon the stationary toothed sector being engaged with the satellite gears which are rotated by the disk and terminates immediately upon the satellite gears and the toothed sector being disengaged. Next, with the disk rotating, the winding members, along with the satellite gears, shift into the winding zone once more, while the carriers with a reserve of the weft thread move into the loom shed.
However, since prior to the engagement of the satellite gears with the toothed sector these satellite gears are in an arbitrary position, there is a probability that any tooth of the satellite gear may collide with a tooth of the sector, which, at high running speeds of the loom, may result in impacts and breakage of the teeth.
Inasmuch as the satellite gears before engaging the toothed sector are stationary, their rotational speed, after meshing therewith, jumps practically instaneously from zero to maximum, thereby causing impacts and premature wearing of the teeth.
Besides, after the satellite gears disengage from the toothed sector, they continues rotating due to inertia before stopping completely and, while rotating due to inertia they continues winding the weft thread onto the spool, since the stoppage by inertia occurs each time at different moments, the length of the wound weft thread varies in each instance, which results in great losses in the weft. Also widely known are toothed winding mechanisms with a device for stopping the same at a definite predetermined position, wherein there are provided a driven gear with two pins and a driving gear with an incomplete number of teeth, combined with a cam. The cam is located in that part of the gear where there are no teeth. Both pins are adapted to cooperate with the cam. As the mechanism operates and the gears are engaged, the driven gear rotates at a constant angular speed. In the process of this rotation, the cam engages two pins, whereby the driven gear is caused to continue the rotation. At this time due to the part without teeth on the driving gear and due to the profile of the cam, the driven gear gradually reduces its speed till a momentary stop. Thereafter, the speed of the driven gear increases to a maximum, the teeth of the driving gear engage the teeth of the driven gear, the cam disengages from the pins and the driven gear again starts rotating at a constant angular speed. While the driving gear makes one revolution, the driven gear makes one revolution and a momentary stop. The profile of the cam ensures impact-free operation of the mechanism. In this mechanism, the probability of collision of the tooth of the driven gear with the tooth of the driving gear is precluded, the mechanism providing for impact-free operation and preventing rotation of the driven gear due to inertia after being disengaged from the driving gear.
However, this apparatus is capable of stopping the driven gear only for a moment. Therefore, it cannot be practically used in the apparatus for winding the weft thread, wherein the winding members must be fixed in a definite position for a long time, i.e., for at least 180.degree. of the disk turn. At the same time, it proves impossible to modify the profile of the cam of this toothed mechanism so as to provide for a prolonged dwell of the driven gear.